<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<script>
    var socket;
    // 判断当前浏览器是否支持websocket
    if (window.WebSocket) {
        // go on
        socket = new WebSocket("ws://localhost:9001/hello");
        // 收到服务器回送的消息
        socket.onmessage = function (ev) {
            var rt = document.getElementById("responseText");
            rt.value = rt.value + "\n" + ev.data;
        }
        // 相当于连接开启
        socket.onopen = function (ev) {
            var rt = document.getElementById("responseText");
            rt.value = "连接开启了。。。"
        }
        // 相当于连接关闭
        socket.onclose = function (ev) {
            var rt = document.getElementById("responseText");
            rt.value = rt.value + "\n" + "连接关闭了。。。";
        }
        // 发送消息到服务器
        function send(message) {
            if (!window.socket) {
                return;
            }
            if (socket.readyState === WebSocket.OPEN) {
                socket.send(message);
            } else {
                alert("连接还没有开启")
            }
        }
    } else {
        alert("当前浏览器不支持websocket")
    }
</script>
    <form onsubmit="return false">
        <textarea name="message" style="height: 300px; width: 300px"></textarea>
        <input type="button" value="发送消息" onclick="send(this.form.message.value)">
        <textarea id="responseText" style="width: 300px; height: 300px"></textarea>
        <input type="button" value="清空内容" onclick="document.getElementById('responseText').value=''">
    </form>
</body>
</html>